Main content

Eric Robson and the panel are at RHS Rosemoor in Devon. Anne Swithinbank, Bob Flowerdew and Mount Stewart's Neil Porteus answer the horticultural questions.

Eric Robson and the panel are at RHS Rosemoor in Devon. Anne Swithinbank, Bob Flowerdew and Mount Stewart's Neil Porteus answer the horticultural questions.

This week, they discuss what to do with an abandoned boat in your garden, how to grow asparagus from seed, and what to plant along two long retaining walls.

The panellists also debate how hard you can cut back a Clematis, advise on dealing with and replacing out-of-control bullrushes, and reveal the naughtiest things they have done in the garden over the years.

And James Wong travels back in time to discover how the Victorians are responsible for our modern passion for terrariums.

Produced by Hannah Newton
Assistant Producer: Laurence Bassett

A Somethin' Else production for BBC Radio 4.

Available now

43 minutes

Last on

Sun 13 May 2018 14:00

Fact Sheet

Q - I moved into a new house with a boat in the garden. What can I do with the boat?

The boat is a wooden dingy - 1.5m wide (5ft) by 3.5m (11.5ft) long 



Bob -  You could maybe turn it into a sitting area or plant potted geraniums and rest them on the seats of the boat.


Anne - What is the rest of the garden like? The soil in the garden - clay 

You could put some hard core substances at the bottom of the boat for some drainage. Give yourself the opportunity to grow something you wouldn't grow in your ordinary soil. You can try grow Mediterranean and drought-tolerant plants You could grow something like Bearded Iris.


Neil - Turn it on its side. Grow some ferns. Something that needs shade. Woodwardia radicans, a couple of cordylines, like it has washed up on the beach artfully. 



Q - This year I have grown asparagus from seed instead of from crowns. I have been left with half a dozen tiny fronds, what do I do now?


Bob - Grow it on in large pots, plant it up. You will have that little frond and underneath will be one or two thick roots.  Keep it well watered.  Grow it up and plant them out next year. Don't forget it’s three years’ growing before you can cut any crop


Neil - If you have someone with an asparagus bed and you are potting up your seedlings as bob has said. Get a pinch of soil from the existing asparagus bed and put it in with your seedlings. It will establish your seedlings much quicker. I do this with rhododendrons and anything I want to grow quickly. hedging plants. The mycorrhizas will help hugely with that plant.



Q - We have moved to a south-facing house with two 40 metre (131ft) long retaining walls.  Can the panel suggest evergreen plants that will trail over the retaining walls, adding interest throughout the year?



Neil - Trachelospermum jasminoides – there’s a form of that called ‘Wilsonii’ which once it finishes has star like flowers that are quite fragrant. The leaves turn red in the winter so you've got something lovely to look at all year round.


Anne - There are some very good rosemary varieties that fall down over the edges of things. There’s one called ‘Foxtail’ and one called ‘Prostratus’ so you could have a whole mass of those given the fact that the soil inside is well drained. They’ll do a very good job of growing vertically and downward hiding the concrete of the wall. 


Bob - Invest in a whole load of window boxes. Stand them at the bottom of the wall and then you have things coming up instead of down.  Try ‘Goldheart’ ivy which have a yellow splash in them which can add colour all year round




Q -  We have a 4-metre-tall (13ft) Bay tree that’s been planted too close to the house. Could I cut it back?


Anne - I would prune it in the spring. May be sensible to dig the whole thing out and replace it with a nearby planting of its own offspring 


Neil - I’d cut it down to the ground. Just keep coppicing it back in early June. It won’t hold any grudges it will grow right back at you. 


Bob - I cut two 20ft high (6m) ones back. I cut them right down to the ground. You won’t destroy them and the young growth provides beautiful red beautiful colours 




After the feature:

Anne - I’ve started to collect rhizomatous ferns. They creep. The leaves are quite interesting. their vertical stems are very nice.   Phlebodium aureum


Q - We have a very wet grass area that we leave uncut. The area is north facing and gets only limited sun and only during summer mornings. Can the panel suggest any plants that I can put into the grass to provide interest through the year? Would any bulbs thrive there?



Anne - Camerisier - a blue flowered bulb.  Camassia quamash from North America - they'd be used as underplanting for roses.  Geranium phaeum and other geraniums, hardy Crane’s-bills that are quite shade tolerant. There are meadow Crane’s-bills as well, Geranium pratense. You want the long fragile ones instead of the close ground-hugging ones. 



Bob - Calla lilies; they don't like drying out. If it’s a very hard winter you may lose some of the more modern colourful ones, but the original ones they go on very easily and they love that continuous moisture. 


Neil - Gunnera perpensa from South Africa.  Farfugium japonicum which is a bit similar. It has these yellow spots on it, they love shady damp conditions. And Chrysosplenium that spreads like a Saxifrage

You've got a choice of things which may do quite nicely. 



Q - I have a Clematis that is approximately 20 years old and it is about to flower. The shed it is growing on has to come down before it falls down. How hard can we cut it back and when is the best time to do this?


Anne - They all have their particular time for being cut back really. I reckon it’s a Clematis montana.  You can let it flower and prune the plant as hard as you want.


Neil - You might find there’s a huge draw of sap when you cut into the old wood. To help the plant because it’s just going to keep pumping this stuff from the roots system, just get some proper charcoal from an old bonfire and use it as a styptic to rub over the wound.


Q - We have a stream running through our garden with a boggy area.  When we moved in three years ago there were three or four bulrushes.  Now there are many more and they are taking over the whole area. How can we get rid of them and what can we put in their place?


Neil - You could actually just dig them out and just leave them by the side of the stream and let all the invertebrates to crawl their way back in before you compost them give them about three weeks and just chuck them on the compost. 

To replace them with, you need some nice marginals that are going to do the thing. I mean Calatheas are lovely, Caltha palustris (the bog marsh-marigold) are lovely for a small stream. Lythrum salicaria (the Loosestrife) is gorgeous.  All the primulas would love it.


Anne - I would add the flowering rush butomus because it puts up leaves that spiral gently. They're not straight like a bulrush. They spiral in a very interesting way and have heads of pretty flowers. If you want something with some sort of vertical interest you can try that or water iris’, some of which are quite invasive and others aren't but they're very easy to control.


Bob - I wouldn't get rid of them. Lots of birds would be using the plants fluff for their nests. Where would the dragonfly climb up if you took the bulrushes away? Where they aren’t maybe you could add some of the other suggestions or something like the Iris pseudoacoris (the Yellow Flag) to add a bit of colour


Q - My garden is a small, rectangular space that I want to plant as a cottage garden. To give it some interest and height I have bought a tall wire obelisk. What would the panel suggest I train up it to give my tiny garden a wow factor?


Neil – It’s a slow business but I like things like Schizophragma which are fantastically showy hydrangea-like plants.   There is a Japanese species called hydrangeoides and even a pink form of that which has these little diamond shaped florets around about June/July but the most showy one is from China one called integrifolium with beautiful white diamond dinner plate like flowers with diamond frills on the outside 


Anne – Etoile d’Hollande rose. it makes itself a good frame for Clematis or Honeysuckle


Bob – Etruscan Honeysuckle


GQT Summer Garden Party

GQT Summer Garden Party

Link to tickets and info

Six of GQT’s naughtiest gardening innuendos

Six of GQT’s naughtiest gardening innuendos

When Gardeners' Question Time got mucky.